Climate Change Factoid - The Greenhouse Effect (1 of a Series)
You cannot plan effectively for your future until you understand what climate change holds for you.
If you decided to do that then the Greenhouse Effect would be the first thing you would want to master.
It's not difficult and you will own it by the time you finish this page.
About 30% of the light arriving from the sun hits our atmosphere and bounces off, back out into space.
The balance of the sun's light continues on, toward the planet's surface, where it will encounter something that is either light or dark in color.
When the surface is light in color, it reflects the sun's light back through the atmosphere and then on out into space.
If the incoming light from the sun encounters a dark colored surface, it is absorbed and then converted into infra red - infra red is heat.
The infra-red then rises into the atmosphere where a very small portion of it will bump into molecules of greenhouse gas, such as Carbon Dioxide (CO2).
When that collision occurs, the greenhouse gas (GHG) molecule begins to vibrate slightly and then it tosses the infra red heat back toward the planet's surface.
That's the greenhouse effect.
If the greenhouse effect did not happen, every night when the heated side of the planet turned away from the sun, the heat collected that day would all escape into space and earth would be turned into an icy and mostly lifeless planet.
You may have already figured out that the quantity of heat that gets reflected back toward earth, depends entirely on how many molecules of greenhouse gas (GHGs) are up there in the atmosphere.
The levels of GHGs in the atmosphere are always changing - slowly.
Over the past few million years the levels of CO2 (the principal GHG) have ranged from a low level of 180 parts per million (ppm) to a high of 280ppm.
It takes about 20,000 years for the GHG levels to rise from that low point (180ppm), to the high point of 280ppm and about 100,000 years to return to the low point.
Then it starts over.
The quantities of CO2 involved are very small -180ppm expressed as a percentage of the entire atmosphere looks like this: 0.
018% or, eighteen one thousandths of one percent.
That still amazes me - that's a very small amount of stuff to be controlling something as important as the temperature of earth.
Historically, at Antarctica where the measurements just mentioned were taken, the temperature increased or decreased 1ºC (1.
8ºF) for every 10ppm change in the level of CO2.
For perspective, the current increase in mean temperature being attributed to human additions of CO2 to the atmosphere, is about 0.
6ºC.
For me, these numbers are so small and take so long to change, that this greenhouse effect looks like a very sensitive system indeed, with very small additions and subtractions (10ppm change caused a 1ºC change in temperature, plus or minus) of GHGs causing profound changes in the natural environment.
As of 2009, we have added 110ppm of CO2 to the normal level of CO2 to the atmosphere - the level is now 390ppm and rising.
Breathtaking, don't you think? (Peer reviewed research, supporting the claims made in this factoid, can be found at the web site shown below)
If you decided to do that then the Greenhouse Effect would be the first thing you would want to master.
It's not difficult and you will own it by the time you finish this page.
About 30% of the light arriving from the sun hits our atmosphere and bounces off, back out into space.
The balance of the sun's light continues on, toward the planet's surface, where it will encounter something that is either light or dark in color.
When the surface is light in color, it reflects the sun's light back through the atmosphere and then on out into space.
If the incoming light from the sun encounters a dark colored surface, it is absorbed and then converted into infra red - infra red is heat.
The infra-red then rises into the atmosphere where a very small portion of it will bump into molecules of greenhouse gas, such as Carbon Dioxide (CO2).
When that collision occurs, the greenhouse gas (GHG) molecule begins to vibrate slightly and then it tosses the infra red heat back toward the planet's surface.
That's the greenhouse effect.
If the greenhouse effect did not happen, every night when the heated side of the planet turned away from the sun, the heat collected that day would all escape into space and earth would be turned into an icy and mostly lifeless planet.
You may have already figured out that the quantity of heat that gets reflected back toward earth, depends entirely on how many molecules of greenhouse gas (GHGs) are up there in the atmosphere.
The levels of GHGs in the atmosphere are always changing - slowly.
Over the past few million years the levels of CO2 (the principal GHG) have ranged from a low level of 180 parts per million (ppm) to a high of 280ppm.
It takes about 20,000 years for the GHG levels to rise from that low point (180ppm), to the high point of 280ppm and about 100,000 years to return to the low point.
Then it starts over.
The quantities of CO2 involved are very small -180ppm expressed as a percentage of the entire atmosphere looks like this: 0.
018% or, eighteen one thousandths of one percent.
That still amazes me - that's a very small amount of stuff to be controlling something as important as the temperature of earth.
Historically, at Antarctica where the measurements just mentioned were taken, the temperature increased or decreased 1ºC (1.
8ºF) for every 10ppm change in the level of CO2.
For perspective, the current increase in mean temperature being attributed to human additions of CO2 to the atmosphere, is about 0.
6ºC.
For me, these numbers are so small and take so long to change, that this greenhouse effect looks like a very sensitive system indeed, with very small additions and subtractions (10ppm change caused a 1ºC change in temperature, plus or minus) of GHGs causing profound changes in the natural environment.
As of 2009, we have added 110ppm of CO2 to the normal level of CO2 to the atmosphere - the level is now 390ppm and rising.
Breathtaking, don't you think? (Peer reviewed research, supporting the claims made in this factoid, can be found at the web site shown below)
Source...